| Diagnostic Codes Table | ||
|---|---|---|
| CDL Code and Description | Conditions which Generate this Code | System Response |
| 336-2 Engine Control Switch : Erratic, Intermittent, or Incorrect | The Electronic Control Module (ECM) detects an intermittent signal for the engine control switch. | The code is logged. |
| 2348-9 SAE J1939 Data Link #2 : Abnormal Update Rate | All communications on this data link have been lost. | The code is logged. |
This procedure verifies the integrity of the Cat Data Link between the following components:
- Service tool connector at the control box connector
- Service tool connector at the display panel
This procedure verifies the integrity of the local CAN data link between the following components:
- Engine Control Module (ECM)
- Temperature Control Module (TCM)
- Fuel control valve
- Service tool connector at the control box connector
This procedure verifies the integrity of the global CAN data link between the following components:
- Engine Control Module (ECM)
- Exhaust temperature module
- Service tool connector at the display panel
If Caterpillar Electronic Technician (ET) will not communicate with the ECM, refer to Troubleshooting, "Electronic Service Tool Does Not Communicate" before you begin this procedure. The procedure verifies that electrical power is being supplied to the engine ECM and to the service tool connector.
The data links provide a communication link between the various control modules on the application.
Cat ET may display the following error message:
"The version of the ECM is not recognized and the integrity of the changed parameters and displayed data is not guaranteed."
If this message is displayed, the flash file in the ECM may be newer than the version of Cat ET, or the latest version of Cat ET has not been installed. Correct this condition prior to continuing with this procedure.
 | |
| Illustration 1 | g01816973 |
Schematic for the local CAN data link | |
 | |
| Illustration 2 | g03197377 |
Schematic for the Cat Data Link | |
 | |
| Illustration 3 | g03197358 |
Schematic for the global CAN data link | |
 | |
| Illustration 4 | g01444702 |
Terminal locations at the service tool connectors that are at the control box (A) +Battery (B) −Battery (C) Local CAN shield (D) Cat Data Link + (E) Cat Data Link − (F) Local CAN data link − (G) Local CAN data link + | |
 | |
| Illustration 5 | g01559974 |
Terminal locations at the P1 ECM connector that are for the data links (P1-8) Cat Data Link + (P1-9) Cat Data Link − (P1-34) Global CAN data link − (P1-42) Global CAN shield (P1-48) +Battery (P1-50) Global CAN data link + (P1-52) +Battery (P1-53) +Battery (P1-55) +Battery (P1-57) +Battery (P1-61) −Battery (P1-63) −Battery (P1-65) −Battery (P1-67) −Battery (P1-69) −Battery (P1-70) Keyswitch | |
 | |
| Illustration 6 | g01326307 |
Terminal locations at the P2 ECM connector that are for the data link (P2-11) Local CAN data link − (P2-12) Local CAN data link + (P2-23) Local CAN shield | |
 | |
| Illustration 7 | g03345128 |
Locations of the connectors that are associated with the data links. (Control box may not be located on engine.) (1) Right rail connector (2) J1/P1 ECM connectors (3) J2/P2 ECM connectors (4) Connector for the CAN shield jumper (5) Service tool connector at the control box (6) Termination resistor for the local CAN data link (7) Termination resistor for the global CAN data link (8) Control box connector for the front harness (9) Engine interface connector | |
 | |
| Illustration 8 | g01355248 |
Terminal locations at the termination resistors (A) CAN data link + (B) CAN data link − (C) Shield | |
 | |
| Illustration 9 | g01559993 |
Terminal locations at the control box for the right rail connector (Terminal 57) Global CAN data link + (Terminal 58) Global CAN data link − (Terminal 59) Global CAN data link shield | |
 | |
| Illustration 10 | g02586016 |
Terminal locations at the engine interface connector (Terminal 8) Cat Data Link + (Terminal 9) Cat Data Link − (Terminal 34) Global CAN data link 1 − (primary) (Terminal 42) Global CAN data link 1 shield (primary) (Terminal 50) Global CAN data link 1 + (primary) (Terminal 57) Global CAN data link 2 − (secondary) (Terminal 64) Global CAN data link 2 shield (secondary) (Terminal 69) Global CAN data link 2 + (secondary) | |
 | |
| Illustration 11 | g01559994 |
Terminal locations at the control box for the front harness (Terminal 13) Local CAN data link + (Terminal 15) Local CAN data link − (Terminal 18) Local CAN data link shield | |
 | |
| Illustration 12 | g02586036 |
Terminal locations at the connector for the jacket water control module and SCAC temperature control module that are for the CAN data link (Terminal 4) Local CAN data link + (Terminal 6) Local CAN data link − (Terminal 9) Local CAN data link shield | |
 | |
| Illustration 13 | g01218763 |
Terminal locations at the connector for the CAN shield jumper (Terminal 1) Local CAN data link shield (Terminal 2) −Battery | |
| Troubleshooting Test Steps | Values | Results |
|---|---|---|
1. Inspect the Electrical Connectors and the Wiring Note: Carefully follow this procedure in order to identify an intermittent problem. A. Perform a visual inspection of the wiring between the P1 and P2 ECM connectors, the termination resistors, the service tool connector, all of the control box connectors, and the connectors at various controllers. - Look for these problems: - Harness damage that is caused by chafing - Harness damage that is caused by excessive heat - Look for moisture on the wiring and in the connectors. - Pull on the wires that are associated with the data links. This test verifies that the wire is properly crimped to the terminal and that the terminal is properly inserted into the connector. |
Connectors |
Results: The wiring and the connectors appear to be OK. Proceed to Test Step 2 Results: There is a problem with the wiring or with a connector. Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the connector seals are properly in place and ensure that the connectors are coupled. Verify that the problem is resolved. |
2. Bypass the Wiring for the Data Link A. Connect the 217-0113 Wiring Harness (ECM BYPASS) to the J1 connector, to the 332-7381 Data Link Cable As, and to the battery. B. Try to establish communication between Cat ET and the ECM. |
Data link |
Results: Cat ET and the ECM communicate. Repair Cat ET and the ECM communicate when the bypass harness is installed. However, communication cannot be established via the engine wiring. Disconnect the electrical connector from each of the control modules that is on the data link one at a time. This test will isolate the problem. Try to establish communication between Cat ET and the ECM after disconnecting each module. The problem is in the control module if disconnecting the module allows Cat ET and the ECM to communicate. If a module is suspect, replace the module. Verify that the problem is resolved. The control module is OK if the problem remains when the module is disconnected. Results: ET and the ECM do not communicate. Repair Communication between Cat ET and the ECM is not established when the bypass harness is installed. Temporarily connect a test ECM. Refer to Troubleshooting, "Test ECM Mode". Verify that the problem is resolved. Connect the original ECM and verify that the problem returns. Before you consider permanently replacing the ECM, consult with the Dealer Solutions Network (DSN). |
3. Check the Wiring for the Data Links for a Short Circuit A. Turn the power disconnect switch to the OFF position. B. Disconnect the negative cable from the battery. C. Disconnect the P1 and P2 ECM connectors from the primary ECM. D. Measure the resistance between the following terminals at the primary ECM: - P1-8 (Cat Data Link +) and P1-61 (-Battery) - P1-9 (Cat Data Link -) and P1-61 (-Battery) - P1-34 (Global CAN data link -) and P1-61 (-Battery) - P1-50 (Global CAN data link +) and P1-61 (-Battery) - P2-11 (Local CAN data link -) and P1-61 (-Battery) - P2-12 (Local CAN data link +) and P1-61 (-Battery) E. Measure the resistance between the following terminals at the primary ECM: - P1-8 (Cat Data Link +) and P1-52 (+Battery) - P1-9 (Cat Data Link -) and P1-52 (+Battery) - P1-34 (Global CAN data link -) and P1-52 (+Battery) - P1-50 (Global CAN data link +) and P1-52 (+Battery) - P2-11 (Local CAN data link -) and P1-52 (+Battery) - P2-12 (Local CAN data link +) and P1-52 (+Battery) |
Short Circuit |
Results: Each measurement indicates an open circuit. The wiring for the data links does not have a short circuit. Proceed to Test Step 4. Results: At least one measurement does not indicate an open circuit. Repair: At least one measurement is less than five Ohms. The wiring for a data link has a short circuit. Determine the cause of the short circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. |
4. Check the Wiring for the Data Links for an Open Circuit A. Connect a jumper wire between terminals P1-8 and P1-9 at the primary ECM. B. At the service tool connector and the connector for each control module, measure the resistance between the terminals for the Cat Data Link. C. Connect a jumper wire between terminals P1-34 and P1-50 D. At each service tool connector measure the resistance between the terminals for the CAN data link. Also, at the connector for each control module on the global network, measure the resistance between the terminals for the CAN data link. E. Connect a jumper wire between terminals P2-11 and P2-12 F. At each service tool connector measure the resistance between the terminals for the CAN data link. Also, at the connector for each control module on the global network, measure the resistance between the terminals for the CAN data link. |
Open circuit |
Results: All of the resistance measurements indicate a short circuit. Repair: If you are troubleshooting the Cat Data Link, the data link appears to be OK. The problem is probably an intermittent problem in a connector or in the harness. If the problem persists, perform this test procedure again. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems. If you are troubleshooting the CAN data link, remove the jumper wires. Leave the control modules disconnected from the data link Proceed to Test Step 5 Results: At least one of the resistance measurements indicates an open circuit. Repair: Determine the cause of the open circuit. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. |
5. Check the Termination Resistors for the J1939 Data Link Perform this test step only if you are troubleshooting a problem with the CAN data link. A. Ensure that all of the control modules are disconnected from the data link. At the service tool connector, measure the resistance between the terminals for the CAN data link. |
45 Ohms and 75 Ohms |
Results: The resistance is between 45 Ohms and 75 Ohms. Repair: The termination resistors are OK. The data link appears to be OK. The problem is probably an intermittent problem in a connector or in the harness. If the problem persists, perform this test procedure again. If an intermittent problem is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect" for information that is related to troubleshooting intermittent electrical problems Results: The resistance is approximately 120 Ohms. There is a problem with a termination resistor. Repair: Determine the cause of the missing termination resistor. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. Results: The resistance is greater than 140 ohms. There is a problem with both termination resistors. Repair: Determine the cause of the problem. Repair the problem, when possible. Replace parts, if necessary. Verify that the problem is resolved. |